Autonomous vehicle

Abstract

To prevent a person from feeling uncomfortable.SOLUTION: The autonomous vehicle includes a camera arranged to capture an image of a road surface, a light emitting diode that emits light to the road surface, an auxiliary storage device that stores map data in which map image data obtained by capturing an image of the road surface in advance and position information are associated with each other, and a control unit. The control unit determines an imaging frequency of the camera from a speed of the autonomous traveling vehicle, causes the light emitting diode to emit light at a timing at which imaging of the camera is performed, determines a blinking frequency avoiding the first frequency band, and estimates a self-position by collating image data acquired from the camera with map image data.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to autonomous vehicles. [Background technology]

[0002] The autonomous vehicle disclosed in Patent Document 1 includes a camera, a light-emitting diode, a storage device, and a control unit. The camera is positioned to capture an image of the road surface. The light-emitting diode irradiates the road surface with light. The storage device stores map data. The map data is data that links map image data, which is a pre-image of the road surface, with location information. The control unit acquires the image data from the camera. The control unit estimates the vehicle's own location by matching the image data with the map image data. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-166853 Summary of the Invention [Problem to be solved by the invention]

[0004] When estimating the vehicle's own position using image data obtained by capturing images of the road surface, it is necessary to illuminate the road surface with light. Constantly emitting light-emitting diodes consumes a lot of power. Therefore, the control unit reduces power consumption by blinking the light-emitting diodes. However, the blinking light can be unpleasant for people. [Means for solving the problem]

[0005] An autonomous vehicle that solves the above problem is an autonomous vehicle that includes a camera positioned to capture images of the road surface, a light-emitting diode that shines light onto the road surface, a memory device that stores map data that links map image data obtained by previously capturing an image of the road surface with location information, and a control unit that controls the blinking frequency of the light-emitting diode, wherein the control unit determines the imaging frequency of the camera from the speed of the autonomous vehicle, determines the blinking frequency so that the light-emitting diode emits light when the camera captures an image and avoids specific frequency bands, and estimates its own position by comparing the image data obtained from the camera with the map image data.

[0006] The control unit controls the light-emitting diode to emit light at a blinking frequency that avoids a specific frequency band, thereby preventing the blinking of the light-emitting diode from causing discomfort to people. With respect to the autonomous vehicle, the control unit may set the imaging frequency and the blinking frequency to values ​​lower than a lower limit value of the specific frequency band when the autonomous vehicle is stopped.

[0007] With regard to the above-mentioned autonomous vehicle, when the autonomous vehicle is moving, the control unit may set the imaging frequency to a value within the range of the specific frequency band, and set the blinking frequency to a value higher than the upper limit value of the specific frequency band.

[0008] For the above-mentioned autonomous vehicle, the control unit may determine whether or not other autonomous vehicles are parked nearby, and if the autonomous vehicle is parked and it is determined that the other autonomous vehicles are parked, determine the blinking frequency to synchronize with the light-emitting diodes of the other autonomous vehicles.

[0009] With regard to the above-mentioned autonomous vehicle, the control unit may determine whether or not there is a person present in the vicinity, and if the autonomous vehicle is moving and it is determined that there is a person present, the flashing frequency may be set to a value higher than the upper limit value of the specific frequency band. [Effects of the Invention]

[0010] According to the present invention, discomfort to people can be suppressed. [Brief explanation of the drawings]

[0011] [Figure 1] Figure 1 is a side view of an autonomous vehicle. [Figure 2] Figure 2 is a schematic diagram of an autonomous vehicle. [Figure 3] FIG. 3 is a diagram showing the first frequency band and the second frequency band. [Figure 4] FIG. 4 is a flowchart showing the self-position estimation control performed by the control unit. [Figure 5] FIG. 5 is a diagram showing the relationship between the speed of the autonomous vehicle and the imaging frequency. [Figure 6] FIG. 6 is a diagram showing the relationship between the speed of the autonomous vehicle and the blinking frequency. [Figure 7] FIG. 7 is a flowchart showing the self-position estimation control performed by the control unit. [Figure 8] FIG. 8 is a diagram showing the relationship between the speed of the autonomous vehicle and the imaging frequency and the blinking frequency. [Figure 9] FIG. 9 is a diagram showing the relationship between the speed of the autonomous vehicle and the imaging frequency and the blinking frequency. DETAILED DESCRIPTION OF THE INVENTION

[0012] An embodiment of an autonomous vehicle will now be described. <Autonomous Vehicles> As shown in FIGS. 1 and 2 , autonomous vehicle 10 includes vehicle body 11, drive wheels 21, travel motor driver 22, travel motor 23, steering wheels 31, steering motor driver 32, and steering motor 33. Autonomous vehicle 10 may be a passenger car or an industrial vehicle. Industrial vehicles include, for example, forklifts, towing tractors, or automated guided vehicles. Autonomous vehicle 10 may be capable of only autonomous driving, or may be capable of switching between autonomous driving and manual driving.

[0013] Travel motor 23 is a motor for rotating drive wheels 21. Travel motor driver 22 drives travel motor 23. Drive of travel motor 23 rotates drive wheels 21, causing autonomous vehicle 10 to travel. Steering motor 33 is a motor for steering steering wheels 31. Steering motor driver 32 drives steering motor 33. Drive of steering motor 33 steers steering wheels 31, causing autonomous vehicle 10 to turn.

[0014] The autonomous vehicle 10 includes a camera 41. The camera 41 is a digital camera. The camera 41 includes an image sensor. The image sensor is, for example, a charge coupled device (CCD) image sensor or a complementary metal oxide semiconductor (CMOS) image sensor. The camera 41 is, for example, an RGB camera, an infrared camera, a grayscale camera, or a visible light camera.

[0015] The camera 41 is positioned to capture an image of the road surface Sr. The camera 41 generates image data showing the captured image of the road surface Sr. The camera 41 is mounted on the bottom of the vehicle body 11 facing vertically. More specifically, the camera 41 is mounted so that the optical axis of the camera 41 coincides with the vertical direction. The state in which the camera 41 faces vertically allows for errors due to the mounting accuracy of the camera 41, and the camera 41 may be mounted facing in a direction slightly deviated from the vertical direction.

[0016] The autonomous vehicle 10 includes a light-emitting diode 51 and an LED driver 52 that controls the light-emitting diode 51. The light-emitting diode 51 emits light onto the road surface Sr. Specifically, the light-emitting diode 51 emits light onto a portion of the road surface Sr that is within the imaging range of the camera 41. The light-emitting diode 51 is provided on the bottom of the vehicle body 11 and faces vertically. The LED driver 52, for example, passes a current through the light-emitting diode 51 to energize and cut off the current flow to the light-emitting diode 51. When current is passed through the light-emitting diode 51, the light-emitting diode 51 emits light.

[0017] Autonomous vehicle 10 includes speed sensor 61. Speed ​​sensor 61 detects the speed of autonomous vehicle 10. Speed ​​sensor 61 is, for example, a rotation speed sensor that detects the rotation speed of traction motor 23.

[0018] Autonomous vehicle 10 includes an auxiliary storage device 71. Auxiliary storage device 71 is, for example, a hard disk drive, a solid state drive, or a flash memory. Auxiliary storage device 71 stores map data M1. Map data M1 associates map image data obtained by capturing a road surface Sr in advance with position information. The range in which autonomous vehicle 10 travels is determined in advance. The position information includes coordinates and attitude. The coordinates are coordinates in a map coordinate system, which is a coordinate system that represents absolute positions. The map coordinate system may be a Cartesian coordinate system or a geographic coordinate system. The map coordinate system includes an X-axis and a Y-axis. The X-axis and Y-axis are orthogonal to each other. The X-axis and Y-axis are coordinate systems that represent the horizontal direction. The attitude is information that indicates the inclination of autonomous vehicle 10 with respect to the coordinate axes of the map coordinate system. Map data M1 is data that represents the coordinates in the map coordinate system of the range in which autonomous vehicle 10 travels and the attitude. The auxiliary storage device 71 is an example of a storage device that stores the map data M1.

[0019] The autonomous vehicle 10 includes a control unit 81. The control unit 81 includes a processor 82 and a memory unit 83. The processor 82 is, for example, a central processing unit (CPU), a graphics processing unit (GPU), or a digital signal processor (DSP). The memory unit 83 includes a random access memory (RAM) and a read-only memory (ROM). The memory unit 83 stores program code or instructions configured to cause the processor 82 to execute processing. The memory unit 83, i.e., a computer-readable medium, includes any available medium accessible by a general-purpose or special-purpose computer. The control unit 81 may be configured by a hardware circuit such as an application-specific integrated circuit (ASIC) or a field-programmable gate array (FPGA). The control unit 81, which is a processing circuit, may include one or more processors operating according to a computer program, one or more hardware circuits such as an ASIC or an FPGA, or a combination thereof.

[0020] Control unit 81 controls autonomous vehicle 10. For example, control unit 81 causes autonomous vehicle 10 to travel by issuing commands to travel motor driver 22 and steering motor driver 32.

[0021] The control unit 81 controls the camera 41. The control unit 81 determines the imaging frequency IF of the camera 41 and causes the camera 41 to capture images in accordance with the imaging frequency IF. The imaging frequency IF represents the number of times the camera 41 captures images per second. 1 [Hz] represents one image capture per second. The imaging cycle of the camera 41 is 1 / imaging frequency IF.

[0022] The control unit 81 controls the light-emitting diode 51. The control unit 81 determines the blinking frequency FF of the light-emitting diode 51 and causes the light-emitting diode 51 to emit light in accordance with the blinking frequency FF. For example, the control unit 81 outputs a command to the LED driver 52, thereby causing the LED driver 52 to control the light-emitting diode 51 to emit light at the blinking frequency FF. The blinking frequency FF represents the number of times the light-emitting diode 51 emits light per second. 1 [Hz] represents one light emission per second. The blinking cycle of the light-emitting diode 51 is 1 / blinking frequency FF.

[0023] As shown in Fig. 3, the blinking frequency FF includes a first frequency band FB1 and a second frequency band FB2. The first frequency band FB1 is a specific frequency band. The first frequency band FB1 is a frequency band that may cause discomfort to people when the light-emitting diodes 51 are caused to emit light at a blinking frequency FF within the range of the first frequency band FB1. It is known that blinking of light may cause discomfort to people, and the higher the blinking frequency FF, the greater the discomfort may be.

[0024] The lower limit of the first frequency band FB1 is, for example, 3 [Hz]. 3 [Hz] is a value set based on guidelines for video techniques such as animation. The flickering frequency FF that causes discomfort to people can vary depending on the surrounding environment, the color of the light, the wavelength of the light, etc. The lower limit of the first frequency band FB1 may be changed based on these factors.

[0025] The upper limit of the first frequency band FB1 is, for example, 50 Hz. As the blinking frequency FF increases, the blinking cycle becomes shorter. When the blinking cycle becomes shorter, people cannot perceive the blinking of light and perceive the light-emitting diode 51 as continuously shining. 50 Hz is the value that defines the boundary between whether or not people can perceive the blinking of light. Therefore, if the blinking frequency FF is set higher than the upper limit of the first frequency band FB1, the discomfort caused to people by the blinking of light is reduced. The upper limit of the first frequency band FB1 may also be changed depending on the surrounding environment, the color of light, the wavelength of light, etc.

[0026] The second frequency band FB2 is a frequency band that may attract insects when the light-emitting diode 51 is caused to emit light at a flashing frequency FF within the range of the second frequency band FB2. The lower limit of the second frequency band FB2 is higher than the upper limit of the first frequency band FB1. Therefore, even when the light-emitting diode 51 is caused to emit light at a flashing frequency FF within the range of the second frequency band FB2, it is unlikely to cause discomfort to people. On the other hand, the flashing frequency FF at which insects can perceive the flashing of light is higher than that of humans, so there is a risk of attracting insects. The lower limit of the second frequency band FB2 is, for example, 100 [Hz]. The upper limit of the second frequency band FB2 is, for example, 120 [Hz].

[0027] 2, autonomous vehicle 10 includes battery 90. Battery 90 is a power source for electrical components included in autonomous vehicle 10. The electrical components include camera 41 and light-emitting diode 51.

[0028] <Self-position estimation control performed by the control unit> Control unit 81 repeatedly performs self-position estimation control. Control unit 81 drives autonomous vehicle 10 based on the self-position estimated by self-position estimation control. For example, control unit 81 generates a driving route and drives autonomous vehicle 10 so that the self-position moves along the driving route.

[0029] As shown in FIG. 4, in step S1, control unit 81 acquires the speed of autonomous vehicle 10 from speed sensor 61. Next, in step S2, control unit 81 determines whether autonomous vehicle 10 is stopped. Control unit 81 determines whether the speed of autonomous vehicle 10 acquired in step S1 is less than vehicle stop determination threshold T1. Vehicle stop determination threshold T1 is a threshold for determining whether autonomous vehicle 10 is stopped. Vehicle stop determination threshold T1 can be set to any value within a range of 1 to 3 km / h, for example. Control unit 81 determines that autonomous vehicle 10 is stopped when the speed of autonomous vehicle 10 is less than vehicle stop determination threshold T1. Control unit 81 determines that autonomous vehicle 10 is moving when the speed of autonomous vehicle 10 is equal to or greater than vehicle stop determination threshold T1. If the determination result in step S2 is positive, control unit 81 proceeds to step S3. If the determination result in step S2 is negative, control unit 81 proceeds to step S5.

[0030] In step S3, the control unit 81 determines the imaging frequency IF. As shown in FIG. 5, the imaging frequency IF is determined according to the speed of autonomous vehicle 10. In the example shown in FIG. 5, control unit 81 gradually increases the imaging frequency IF as the speed of autonomous vehicle 10 increases. In this embodiment, control unit 81 changes the imaging frequency IF in two stages. When the speed of autonomous vehicle 10 is less than vehicle stop determination threshold T1, that is, when control unit 81 determines that autonomous vehicle 10 is stopped, control unit 81 sets the imaging frequency IF to first imaging frequency F1. As shown in FIG. 3, first imaging frequency F1 is a value lower than the lower limit of first frequency band FB1. First imaging frequency F1 is, for example, 1 Hz.

[0031] 4, next, in step S4, the control unit 81 determines a blinking frequency FF so as to avoid the first frequency band FB1 and to make the light emitting diode 51 emit light at the timing when the camera 41 captures an image. When the light emitting diode 51 emits light at the timing when the camera 41 captures an image, the blinking frequency FF can be determined to be a multiple of the imaging frequency IF.

[0032] As shown in Fig. 6, the blinking frequency FF is determined according to the speed of autonomous vehicle 10. Control unit 81 gradually increases the blinking frequency FF as the speed of autonomous vehicle 10 increases. In this embodiment, control unit 81 changes the blinking frequency FF in two stages. If the speed of autonomous vehicle 10 is less than threshold T1 for determining whether autonomous vehicle 10 is stopped, that is, if control unit 81 determines that autonomous vehicle 10 is stopped, it sets the imaging frequency IF to first blinking frequency F11.

[0033] As shown in FIG. 3, the first blinking frequency F11 is a value lower than the lower limit of the first frequency band FB1. The first blinking frequency F11 is a value that is a multiple of the first imaging frequency F1. If the first imaging frequency F1 is 1 [Hz], the first blinking frequency F11 may be 1 [Hz], which is 1 time the first imaging frequency F1. The first blinking frequency F11 may be 2 [Hz], which is twice the first imaging frequency F1. The higher the blinking frequency FF, the greater the power consumption. For this reason, it is preferable that the first blinking frequency F11 be 1 time the first imaging frequency F1. As described above, when the control unit 81 determines that the autonomous vehicle 10 is stopped, it sets the imaging frequency IF and the blinking frequency FF to values ​​lower than the lower limit of the first frequency band FB1.

[0034] 4, in step S5, control unit 81 determines imaging frequency IF. If the speed of autonomous vehicle 10 is equal to or greater than vehicle stop determination threshold T1, that is, if control unit 81 determines that autonomous vehicle 10 is moving, control unit 81 sets imaging frequency IF to second imaging frequency F2.

[0035] As shown in Fig. 3, the second imaging frequency F2 is a value higher than the first imaging frequency F1. The second imaging frequency F2 may be a value within the range of the first frequency band FB1. The second imaging frequency F2 can be set arbitrarily within the range of 10 to 30 Hz, for example. The first imaging frequency F1 and the second imaging frequency F2 are preset values.

[0036] 4, next, in step S6, control unit 81 causes light-emitting diode 51 to emit light at the timing when image capturing is performed by camera 41, and determines blinking frequency FF while avoiding first frequency band FB1. If control unit 81 determines that the speed of autonomous vehicle 10 is equal to or greater than threshold T1 for determining whether autonomous vehicle 10 is stopped, that is, if control unit 81 determines that autonomous vehicle 10 is moving, it determines blinking frequency FF to be second blinking frequency F12.

[0037] As shown in Fig. 3, the second blinking frequency F12 is a value higher than the upper limit of the first frequency band FB1. The second blinking frequency F12 is a value that is a multiple of the second imaging frequency F2. For example, if the second imaging frequency F2 is 10 [Hz], the second blinking frequency F12 may be 10 times that frequency, such as 100 [Hz], or 11 times that frequency, such as 110 [Hz]. The second blinking frequency F12 may be a value within the range of the second frequency band FB2.

[0038] 4, after the processing of step S4 or step S6 is performed, the control unit 81 performs the processing of step S7. In step S7, the control unit 81 captures an image at the imaging frequency IF determined in step S3 or step S5. The control unit 81 causes the light-emitting diode 51 to emit light at the blinking frequency FF determined in step S4 or step S6. As the camera 41 captures an image, the control unit 81 acquires image data captured by the camera 41.

[0039] When light-emitting diode 51 is caused to emit light at blinking frequency FF determined in step S6, the blinking cycle of light-emitting diode 51 becomes shorter than the image capturing cycle of camera 41. Therefore, light-emitting diode 51 emits light even when camera 41 is not capturing images.

[0040] Next, in step S8, the control unit 81 performs self-location estimation. First, the control unit 81 compares the image data with map image data. The control unit 81 extracts feature points from the image data. The control unit 81 describes the feature amounts of the feature points. The feature amounts are, for example, feature amount vectors or brightness values. The control unit 81 also extracts feature points and describes the feature amounts using the map image data. The control unit 81 compares the feature points and feature amounts obtained from the image data with the feature points and feature amounts obtained from the map image data, and searches for pairs of feature points with similar feature amounts. The control unit 81 identifies map image data corresponding to the image data based on the feature point pairs. For example, the control unit 81 identifies map image data in which feature point pairs are concentrated as map image data corresponding to the image data. The above-mentioned matching can be performed using feature amount descriptors. The feature descriptor is, for example, Oriented Fast and Rotated Brief (ORB), Scale-Invariant Feature Transform (SIFT), or Speeded Up Robust Features (SURF).

[0041] The control unit 81 estimates its own position based on the map image data. The own position includes the coordinates of the autonomous vehicle 10 in a map coordinate system and the attitude of the autonomous vehicle 10. The control unit 81 calculates the relative position between the map image data and the image data, and the relative angle between the map image data and the image data. The relative position between the map image data and the image data is the amount of deviation between the image data and the map image data. The relative angle between the image data and the map image data is the angle of deviation between the image data and the map image data. The image data and the map image data often do not match perfectly. This is because the position and attitude of the autonomous vehicle 10 rarely match perfectly between the time the map image data is acquired and the time the image data is acquired. For this reason, the image data often only matches part of the map image data. If the position of the autonomous vehicle 10 is different between the time the map image data is acquired and the time the image data is acquired, the difference in the position of the autonomous vehicle 10 will cause a deviation between the position of the road surface Sr shown in the map image data and the position of the road surface Sr shown in the image data. This amount of deviation is the relative position between the map image data and the image data. The amount of deviation can be determined from the positional relationship between feature points in the map image data and feature points in the image data. Similarly, the difference in the attitude of autonomous vehicle 10 between the time the map image data was acquired and the time the image data was acquired results in the image data being a rotated version of the map image data. The angle of deviation resulting from this rotation is the relative angle between the image data and the map image data. Control unit 81 estimates its own position based on the position information, relative position, and relative angle associated with the map image data. Control unit 81 shifts the coordinates associated with the map image data by the coordinates corresponding to the relative position. Control unit 81 shifts the attitude associated with the map image data by the relative angle. Control unit 81 regards the coordinates and attitude in the map coordinate system obtained as a result as its own position.

[0042] [Operation of this embodiment] When autonomous vehicle 10 is stopped, control unit 81 sets blinking frequency FF to first blinking frequency F11. When autonomous vehicle 10 is traveling, control unit 81 sets blinking frequency FF to second blinking frequency F12. First blinking frequency F11 and second blinking frequency F12 are frequencies that avoid first frequency band FB1. Therefore, light-emitting diode 51 can be made to emit light at blinking frequency FF that avoids first frequency band FB1.

[0043] [Effects of this embodiment] (1) The control unit 81 causes the light-emitting diode 51 to emit light at the blinking frequency FF that avoids the first frequency band FB1, thereby making it possible to prevent the blinking of the light-emitting diode 51 from causing discomfort to people.

[0044] (2) When the control unit 81 determines that the autonomous vehicle 10 is stopped, it sets the imaging frequency IF and the blinking frequency FF to values ​​lower than the lower limit of the first frequency band FB1. When the autonomous vehicle 10 is stopped, the position of the autonomous vehicle 10 does not change, or the change in the position of the autonomous vehicle 10 is slight. Therefore, the control unit 81 may perform self-position estimation less frequently. The blinking frequency FF needs to be a value that avoids the first frequency band FB1 and is a multiple of the imaging frequency IF. Therefore, when the imaging frequency IF is set to a value equal to or higher than the lower limit of the first frequency band FB1, the blinking frequency FF needs to be set to a value higher than the upper limit of the first frequency band FB1. By setting the imaging frequency IF to a value lower than the lower limit of the first frequency band FB1, the blinking frequency FF can be set to a value lower than the lower limit of the first frequency band FB1. The lower the blinking frequency FF of the light-emitting diode 51, the less power is consumed by the light-emitting diode 51. Compared to when the blinking frequency FF is higher than the upper limit value of the first frequency band FB1, power consumption is reduced.

[0045] Furthermore, since the blinking frequency FF is not within the range of the second frequency band FB2, the attraction of insects is also suppressed. If insects are attracted, they may appear in the image data, which could reduce the accuracy of the self-location estimation. By determining the blinking frequency FF so as to avoid the second frequency band FB2, it is possible to prevent the accuracy of the self-location estimation from decreasing.

[0046] (3) When it is determined that autonomous vehicle 10 is traveling, control unit 81 sets imaging frequency IF to a value within the range of first frequency band FB1 and sets blinking frequency FF to a value higher than the upper limit of first frequency band FB1. When autonomous vehicle 10 is traveling, the position of autonomous vehicle 10 fluctuates, and therefore, it is necessary to perform self-position estimation more frequently than when autonomous vehicle 10 is stopped. For this reason, by increasing imaging frequency IF, imaging frequency IF is included in first frequency band FB1. Control unit 81 sets blinking frequency FF to a value higher than the upper limit of first frequency band FB1. In this case, the blinking cycle of light-emitting diode 51 is shorter than the imaging cycle of camera 41, so light-emitting diode 51 emits light even when camera 41 is not capturing images. Because blinking frequency FF is a multiple of imaging frequency IF, light-emitting diode 51 emits light when camera 41 is capturing images. As a result, even if the imaging frequency IF is a value within the range of the first frequency band FB1, it is possible to cause the light emitting diode 51 to emit light at the timing when the camera 41 takes an image, while suppressing discomfort to people.

[0047] The blinking frequency FF may take a value within the range of the second frequency band FB2. When autonomous vehicle 10 is traveling, insects are less likely to approach autonomous vehicle 10 due to fluctuations in the position of autonomous vehicle 10 and the influence of wind while autonomous vehicle 10 is traveling. Since insects are less likely to appear in image data, the accuracy of estimating the vehicle's own position is less likely to decrease even if the blinking frequency FF takes a value within the range of the second frequency band FB2.

[0048] [Example of change] The embodiment can be modified as follows: The embodiment and the following modifications can be combined with each other to the extent that they are not technically inconsistent.

[0049] When the control unit 81 determines that the autonomous vehicle 10 is stopped, it may determine whether or not other autonomous vehicles are stopped nearby. When the control unit 81 determines that the autonomous vehicle 10 is stopped and that other autonomous vehicles are stopped nearby, it may determine the blinking frequency FF to synchronize with the light-emitting diodes of the other autonomous vehicles. For example, the control unit 81 may perform the self-position estimation control shown in FIG. 7. In the following explanation, differences from the self-position estimation control of the embodiment will be explained. Processing similar to that of the embodiment will be assigned the same reference numerals as those of the embodiment, and explanations thereof will be omitted. The other autonomous vehicles have the same configuration as the autonomous vehicle 10.

[0050] As shown in FIG. 7, if the determination result in step S2 is positive, the control unit 81 proceeds to step S11. In step S11, the control unit 81 acquires information indicating the surrounding situation. The information indicating the surrounding situation in step S11 is information for determining whether other autonomous vehicles are parked in the vicinity. For example, the information indicating the surrounding situation is information indicating the positions of the other autonomous vehicles and whether the other autonomous vehicles are parked. This information can be acquired, for example, from the other autonomous vehicles or a traffic management system. The traffic management system is a system that comprehensively manages the operation of autonomous vehicle 10 and the other autonomous vehicles. As shown in FIG. 2, autonomous vehicle 10 may be equipped with a wireless device 91 to acquire information from the other autonomous vehicles or the traffic management system. The other autonomous vehicles may transmit their own positions estimated by self-position estimation and information indicating whether they are traveling to autonomous vehicle 10 or the traffic management system.

[0051] Next, in step S12, control unit 81 determines whether or not other autonomous vehicles are parked nearby. Control unit 81 determines whether or not other autonomous vehicles are parked within a predetermined range from the self-position of autonomous vehicle 10. The predetermined range is, for example, a range in which the light from light-emitting diode 51 of autonomous vehicle 10 overlaps with the light from the light-emitting diode of the other autonomous vehicle. If the determination result in step S12 is negative, control unit 81 proceeds to step S3, and thereafter, the same processing as in the embodiment is performed. If the determination result in step S12 is positive, control unit 81 proceeds to step S13.

[0052] In step S13, the control unit 81 determines the imaging frequency IF. The imaging frequency IF may be determined by the same process as in step S3. Next, in step S14, control unit 81 determines blinking frequency FF. Control unit 81 determines blinking frequency FF so as to synchronize with the light-emitting diodes of the other autonomous vehicles. That is, control unit 81 determines blinking frequency FF so that light-emitting diode 51 emits light at the same timing as the light-emitting diodes of the other autonomous vehicles. For example, control unit 81 gradually lowers blinking frequency FF within a range below the lower limit value of first frequency band FB1, thereby gradually matching the light emission timing of the light-emitting diodes of the other autonomous vehicles with that of light-emitting diode 51. Then, when the light emission timing of the light-emitting diodes of the other autonomous vehicles and that of light-emitting diode 51 match, control unit 81 makes blinking frequency FF the same as the blinking frequency of the other autonomous vehicles. This synchronizes light-emitting diode 51 of autonomous vehicle 10 with the light-emitting diodes of the other autonomous vehicles.

[0053] After completing the process of step S14, the control unit 81 proceeds to step S7, whereby the control unit 81 causes the camera 41 to capture an image at the imaging frequency IF determined in step S13, and causes the light-emitting diode 51 to emit light at the blinking frequency FF determined in step S14.

[0054] When autonomous vehicle 10 is stopped, control unit 81 sets blinking frequency FF to a value lower than the lower limit of first frequency band FB1. This reduces the frequency with which light-emitting diode 51 blinks. However, if the light-emitting diodes of other autonomous vehicles are blinking, the light-emitting diodes of the other autonomous vehicles and light-emitting diode 51 may alternately emit light, which could cause blinking frequency FF to substantially fall within the range of first frequency band FB1. In response to this, by determining blinking frequency FF so as to be synchronized with the light-emitting diodes of the other autonomous vehicles, it is possible to reduce discomfort to people even when other autonomous vehicles are stopped nearby.

[0055] When autonomous vehicle 10 is traveling and it is determined that a person is present in the vicinity, control unit 81 may set blinking frequency FF to a value higher than the upper limit value of first frequency band FB1. For example, control unit 81 may perform self-location estimation control as shown in FIG. 7. In the following explanation, differences from the self-location estimation control of the embodiment will be explained. Processing similar to that of the embodiment will be denoted by the same reference numerals as those of the embodiment, and explanations thereof will be omitted.

[0056] As shown in FIG. 7, if the determination result in step S2 is negative, control unit 81 proceeds to step S21. In step S21, control unit 81 acquires information indicating the surrounding situation. The information indicating the surrounding situation in step S21 is information that can determine whether or not a person is present around autonomous vehicle 10. This information is, for example, information indicating an unmanned driving area or the detection result of an obstacle sensor. The information indicating the unmanned driving area may be acquired from map data M1. For example, it may be possible to associate the unmanned driving area with coordinates in a map coordinate system. As shown in FIG. 2, autonomous vehicle 10 may be equipped with an obstacle sensor 92 for detecting the surrounding situation. Obstacle sensor 92 is, for example, a sensor such as a camera or LIDAR that can enable control unit 81 to recognize the outline of an obstacle.

[0057] Next, in step S22, control unit 81 determines whether or not there is a person around autonomous vehicle 10. If an unmanned driving area has been set, control unit 81 determines that there is no person around if the autonomous vehicle's own position is located in an unmanned driving area. Control unit 81 determines that there is a person around if the autonomous vehicle's own position is not located in an unmanned driving area.

[0058] If autonomous vehicle 10 is equipped with obstacle sensor 92, control unit 81 determines whether or not a person is present in the vicinity based on the detection result of obstacle sensor 92. Control unit 81 detects the position of an obstacle based on the detection result of obstacle sensor 92 and determines whether or not the obstacle is a person. Control unit 81 determines whether or not a person is present within a predetermined range from autonomous vehicle 10. The predetermined range is, for example, the range reached by light from light-emitting diode 51. If a person is present within the predetermined range, control unit 81 determines that a person is present in the vicinity.

[0059] If the determination result in step S22 is positive, control unit 81 proceeds to step S5, and thereafter performs the same processing as in the embodiment. As a result, when control unit 81 determines that autonomous vehicle 10 is traveling and that there is a person nearby, it sets blinking frequency FF to a value higher than the upper limit value of first frequency band FB1.

[0060] If the determination result in step S22 is negative, the control unit 81 proceeds to step S23. In step S23, the control unit 81 determines the imaging frequency IF. The imaging frequency IF may be determined by the same process as in step S5.

[0061] Next, in step S24, the control unit 81 determines the blinking frequency FF. At this time, the control unit 81 can set the blinking frequency FF arbitrarily as long as it is a multiple of the imaging frequency IF. When there are no people nearby, there is no need to consider the discomfort it may cause to people, so the blinking frequency FF can be set to a value within the range of the first frequency band FB1. A lower blinking frequency FF can reduce power consumption. For this reason, it is preferable that the blinking frequency FF be set to the same value as the imaging frequency IF. After completing the processing of step S24, the control unit 81 proceeds to step S7. As a result, the control unit 81 captures an image with the camera 41 at the imaging frequency IF determined in step S23, and causes the light-emitting diode 51 to emit light at the blinking frequency FF determined in step S24.

[0062] When the control unit 81 does not determine that a person is present in the vicinity, it can arbitrarily set the blinking frequency FF. Since the blinking frequency FF does not need to be set to a value higher than the upper limit value of the first frequency band FB1, it is possible to reduce power consumption.

[0063] As shown in Fig. 8, control unit 81 may change imaging frequency IF in three or more stages depending on the speed of autonomous vehicle 10. In the example shown in Fig. 8, control unit 81 changes imaging frequency IF in four stages.

[0064] When the speed of autonomous vehicle 10 is less than vehicle stop determination threshold T1, control unit 81 sets the imaging frequency IF to the first imaging frequency F1. When the speed of autonomous vehicle 10 is equal to or greater than vehicle stop determination threshold T1 and less than first speed threshold T2, control unit 81 sets the imaging frequency IF to the second imaging frequency F2. When the speed of autonomous vehicle 10 is equal to or greater than first speed threshold T2 and less than second speed threshold T3, control unit 81 sets the imaging frequency IF to the third imaging frequency F3. When the speed of autonomous vehicle 10 is equal to or greater than second speed threshold T3, control unit 81 sets the imaging frequency IF to the fourth imaging frequency F4.

[0065] The speed thresholds T2 and T3 can be set arbitrarily. The second imaging frequency F2 is higher than the first imaging frequency F1, the third imaging frequency F3 is higher than the second imaging frequency F2, and the fourth imaging frequency F4 is higher than the third imaging frequency F3. The first imaging frequency F1 is lower than the lower limit of the first frequency band FB1. The second imaging frequency F2, the third imaging frequency F3, and the fourth imaging frequency F4 are values ​​within the range of the first frequency band FB1.

[0066] The control unit 81 determines the blinking frequency FF so that it is a multiple of the imaging frequency IF. In the example shown in Fig. 8, when the speed of the autonomous vehicle 10 is less than the vehicle stop determination threshold T1, the control unit 81 sets the blinking frequency FF to the first blinking frequency F11. The first blinking frequency F11 has the same value as the first imaging frequency F1, for example. The first blinking frequency F11 has a value lower than the lower limit of the first frequency band FB1.

[0067] When the speed of autonomous vehicle 10 is equal to or greater than stop determination threshold T1 and less than first speed threshold T2, control unit 81 sets blinking frequency FF to second blinking frequency F12. Second blinking frequency F12 is, for example, 10 times the value of second imaging frequency F2. Second blinking frequency F12 is a value higher than the upper limit of first frequency band FB1. Second blinking frequency F12 may be a value within the range of second frequency band FB2.

[0068] When the speed of autonomous vehicle 10 is equal to or greater than first speed threshold T2 and less than second speed threshold T3, control unit 81 sets blinking frequency FF to second blinking frequency F12. That is, control unit 81 maintains blinking frequency FF at second blinking frequency F12 even when the speed of autonomous vehicle 10 changes and straddles first speed threshold T2. Second blinking frequency F12 is, for example, five times the value of third imaging frequency F3.

[0069] When the speed of the autonomous vehicle 10 is equal to or greater than the second speed threshold T3, the control unit 81 sets the blinking frequency FF to the third blinking frequency F13. The third blinking frequency F13 is, for example, three times the value of the fourth imaging frequency F4. The third blinking frequency F13 is a value lower than the second blinking frequency F12. The third blinking frequency F13 is a value higher than the upper limit value of the first frequency band FB1. The third blinking frequency F13 is a value lower than the lower limit value of the second frequency band FB2.

[0070] As described above, the blinking frequency FF does not need to be increased as the speed of autonomous vehicle 10 increases. Similarly, the imaging frequency IF does not need to be increased as the speed of autonomous vehicle 10 increases. For example, a threshold value may be set for the speed of autonomous vehicle 10, and the imaging frequency IF may be lowered when the speed of autonomous vehicle 10 exceeds the threshold value. In this case, when the speed of autonomous vehicle 10 exceeds the threshold value, self-location estimation may be performed using a method other than self-location estimation using camera 41.

[0071] As shown in Fig. 9, control unit 81 may increase imaging frequency IF in proportion to the speed of autonomous vehicle 10. Control unit 81 may determine blinking frequency FF so that it is a multiple of imaging frequency IF. In the example shown in Fig. 9, when the speed of autonomous vehicle 10 is less than vehicle stop determination threshold T1, control unit 81 sets blinking frequency FF to the same value as imaging frequency IF. In this case, blinking frequency FF is a value lower than the lower limit of first frequency band FB1.

[0072] When the speed of autonomous vehicle 10 is equal to or greater than vehicle stop determination threshold T1 and less than first speed threshold T12, control unit 81 determines blinking frequency FF to be a value higher than the upper limit of first frequency band FB1 and a multiple of imaging frequency IF. Since imaging frequency IF increases in proportion to the speed of autonomous vehicle 10, blinking frequency FF also increases in proportion to the speed of autonomous vehicle 10. Blinking frequency FF is, for example, eight times the imaging frequency IF.

[0073] When the speed of autonomous vehicle 10 reaches first speed threshold T12, control unit 81 reduces the magnification of blinking frequency FF with respect to imaging frequency IF. For example, control unit 81 sets blinking frequency FF to a value four times the imaging frequency IF. First speed threshold T12 is set so that blinking frequency FF remains higher than the upper limit of first frequency band FB1 even when the magnification of blinking frequency FF with respect to imaging frequency IF is reduced.

[0074] When the speed of autonomous vehicle 10 reaches second speed threshold T13, control unit 81 reduces the magnification of blinking frequency FF with respect to imaging frequency IF. For example, control unit 81 sets blinking frequency FF to a value twice the imaging frequency IF. Second speed threshold T13 is set, for example, so that blinking frequency FF remains higher than the upper limit of first frequency band FB1 even when the magnification of blinking frequency FF with respect to imaging frequency IF is reduced.

[0075] When the speed of autonomous vehicle 10 reaches third speed threshold T14, control unit 81 reduces the magnification of blinking frequency FF with respect to imaging frequency IF. For example, control unit 81 sets blinking frequency FF to a value that is 1 times the imaging frequency IF. Third speed threshold T14 is set, for example, so that blinking frequency FF remains higher than the upper limit of first frequency band FB1 even when the magnification of blinking frequency FF with respect to imaging frequency IF is reduced.

[0076] In the above example, when the speed of autonomous vehicle 10 is equal to or greater than stop determination threshold T1, the magnification of blinking frequency FF is changed in stages to prevent blinking frequency FF from becoming excessively high. This prevents blinking frequency FF from becoming excessively high, thereby reducing power consumption.

[0077] The magnification of the blinking frequency FF does not need to be changed when the speed of autonomous vehicle 10 is equal to or greater than threshold value T1 for determining whether autonomous vehicle 10 is stopped. For example, when the speed of autonomous vehicle 10 is equal to or greater than threshold value T1 for determining whether autonomous vehicle 10 is stopped, blinking frequency FF may be maintained at eight times the imaging frequency IF.

[0078] The storage device that stores the map data M1 may be the storage unit 83. [Explanation of symbols]

[0079] M1...map data, Sr...road surface, 10...autonomous vehicle, 41...camera, 51...light-emitting diode, 71...auxiliary storage device which is an example of a storage device, 81...control unit.

Claims

1. a camera positioned to capture an image of the road surface; a light-emitting diode that irradiates light onto the road surface; a storage device that stores map data in which map image data of the road surface captured in advance is linked to location information; a control unit that controls a blinking frequency of the light-emitting diode, The control unit determining an imaging frequency of the camera based on a speed of the autonomous vehicle; The light-emitting diode emits light at a timing when the camera captures an image, and the blinking frequency is determined so as to avoid a specific frequency band; An autonomous vehicle that estimates its own position by comparing the image data acquired from the camera with the map image data.

2. The autonomous vehicle according to claim 1 , wherein the control unit sets the imaging frequency and the blinking frequency to values ​​lower than a lower limit value of the specific frequency band when the autonomous vehicle is stopped.

3. 2. The autonomous vehicle according to claim 1, wherein, when the autonomous vehicle is traveling, the control unit sets the imaging frequency to a value within the specific frequency band and sets the blinking frequency to a value higher than an upper limit value of the specific frequency band.

4. The control unit Determine whether other autonomous vehicles are parked nearby, 3. The autonomous vehicle of claim 2, wherein, when the autonomous vehicle is stopped and it is determined that the other autonomous vehicle is also stopped, the blinking frequency is determined to be synchronized with the light-emitting diodes of the other autonomous vehicle.

5. The control unit Determine whether there are people around, 4. The autonomous vehicle of claim 3, wherein when the autonomous vehicle is moving and it is determined that a person is present, the blinking frequency is set to a value higher than the upper limit value of the specific frequency band.

Images